1.Field of the Invention
This application is a continuation of part of U.S. patent application Ser. No. 11/264,838, which claims the benefit of the earlier filing date of Nov. 1, 2005 now abandoned.
2. Description of the Prior Art
Two neighboring balls in a linear guideway always rotate in the same direction, that is, the contact portions of the two neighboring balls move in opposite direction relative to each other, this will lead to an increase of the friction and resistance of the linear guideway, and will cause unpleasing noise. To solve these problems, the neighboring balls of a linear guideway are usually separated from one another by a plurality of ball retainers.
Currently, the existing ball retainers generally include two types: the first type of ball retainer is an independent unit, and the second type of ball retainer is an assembly consisted of a plurality of independent units that are connected to one another. The ball retainer 41 consisted of a plurality independent units as shown in FIG. 6 comprises a plurality of partitions 411 connected to one another by a flexible chain 412. The partitions 411 are spaced apart from one another to define a plurality spaces with respect to chain 412 for accommodation of a plurality of balls 30. In production of this type of ball retainer 41, the balls 30 must be placed into the mold in advance, this production method has a strict requirement on the quality of the plastic material and the plastic molding machine, thus relatively increasing the production cost. In addition, this special production method makes the balls 30 come into a very tight contact with the partitions 411 of the retainer 41, accordingly, the rotating resistance of the balls 30 will be relatively large.
U.S. Pat. No. 1,224,624 discloses another conventional ball connecting structure, but it is an annular structure used in particularly in bearings but not in linear guideway, therefore, its connecting portion is also annular. Further, the ring portions (for retaining the rolling elements) are assembled to but not integral with the connecting portion, they need to be produced separately and then assembled together, and this is inconvenient.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.